As LSI circuits are increasing in density, circuit linewidths of semiconductor devices are becoming finer. In manufacturing a semiconductor device, an exposure mask (also called a reticle, which is used in a stepper or a scanner) having a circuit pattern is used. An exposure apparatus transfers the pattern to a wafer.
Examples of factors that reduce the yield of manufacturing semiconductor devices include a defect of a pattern formed on a mask or a wafer. There is a need to accurately inspect pattern defects. For example, a known apparatus inspects patterns on a sample for defects by irradiating the sample with a plurality of electron beams (multiple beams) and allowing a detector to detect reflected electrons or secondary electrons released from the sample. The use of multiple beams provides higher throughput of defect inspection than an inspection apparatus using a single electron beam (single beam).
Related-art inspection apparatuses using multiple beams have a disadvantage in that the blur or movement of beams on the surface of the detector causes the beams to be out of a light-receiving area of the detector, leading to reduced inspection accuracy.